Properties of Matter
Matter
Anything that has mass and
takes up space
 Matter can take many forms
and is not always visible to the
eye
 Matter can change form
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Everything in the universe is
made of matter
Energy, thoughts, feelings,
ideas, sounds, light, heat, and
emotions are not matter
Matter is made of atoms
 Matter can neither be created
nor destroyed; it just changes
form - Law of Conservation of
Matter
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Atoms
Tiny particles that make up
matter
 They are so small that 1 million
atoms lined up side by side are
equal to the thickness of a
human hair
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“atom” comes from a Greek
word that means “cannot be
divided”
 Atoms are the smallest unit of
matter that has the identity of
the matter
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Atoms are in turn made of
protons, electrons, and
neutrons
 Protons, electrons, and
neutrons are called subatomic
particles
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Proton
Positively charged particle
 Located in the nucleus of an
atom
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Electron
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Negatively charged particle
Located outside the nucleus of an
atom
Neutron
Neutral particle, no charge
 Located in the nucleus of an
atom
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Types of Matter - Elements
Most kinds of matter are made of
combinations of a basic group of
building blocks called elements
 Element - matter made up of only
one type of atom
 There are about 116 different
elements
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Compounds
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Compounds are matter made up
of different kinds of elements,
chemically bonded together
Compounds
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When elements combine to make
compounds, the new substance
has properties that are different
from the properties of the
elements that made it.
Compounds
Na (sodium) is a very reactive
metal and Cl (chlorine) is a
poisonous gas
 NaCl is table salt and tastes
delicious on potato chips!
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Chemical Formula
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Uses symbols and numbers to represent
the elements found in a substance and
the number of each of those elements
Every element has a 1 to 3 letter
symbol to represent the element, use
the Periodic Table to match the symbol
with the element
Chemical Formula - examples
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NaOH – Has 1 atom of Na (sodium), 1 atom
of O (oxygen) and 1 atom of H (hydrogen)
This is the formula for sodium hydroxide
C6H12O6 – Has 6 atoms of C (carbon), 12
atoms of H (hydrogen) and 6 atoms of O
(oxygen) This is the formula for glucose.
Identifying Elements and
Compounds
Elements and compounds can be
identified by their properties
 Scientists must do different tests
to identify elements and
compounds correctly
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Identifying Elements and
Compounds
It can take several tests and it
helps to compare unknowns with
known examples
 Sometimes scientists also need to
study the atomic and subatomic
structures of matter to make a
correct identification
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Identifying Elements and
Compounds
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There is no simple test to tell
whether a substance is an
element or a compound
Properties
Characteristics or features of a
substance
 Substance – a general term for a
compound or element (a fancy
word for “stuff”)
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Physical Properties
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Characteristics of a substance
that can be measured or
observed without changing the
identity of the substance
Physical Properties: examples
Size
 Shape
 Texture
 Color
 Density
 State of Matter (solid, liquid, gas)
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Physical Properties: Density
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Compares the mass of something
to how much space it takes up
Density = mass/volume
To calculate density, divide the
mass of an object by its volume
Units for density: g/mL or g/cm3
Physical Properties: Density
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Density is a property that can be
used to identify a substance
If you know the density of an
unknown substance, you can
compare it to a list of densities of
known substances and find a
match
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Link to a site with short lessons about
density
http://www.middleschoolchemistry.com
/multimedia/chapter3/lesson1
Physical properties: Solubility
Solubility – ability of one
substance to dissolve in another
(usually a solid in a liquid)
 Soluble substances form
solutions
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Physical properties: Miscibility
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Miscibility – ability of one liquid to
mix with or dissolve in another
liquid
Immiscible liquids don’t mix
Less dense liquid floats on the
denser liquid
Chemical Properties of Matter
A characteristic of a substance
that allows it to change into a
new substance
 Characteristics that relate to the
atomic or elemental
composition of substances
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Chemical Properties of Matter –
Examples
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Examples of chemical properties:
flammability (ability to burn),
ability to react with oxygen,
reactivity (how easily one thing
reacts with another), or
toxicity (how poisonous something
is)
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Link to a site with short lessons about
pH
http://www.middleschoolchemistry.com
/multimedia/chapter6/lesson8
Lessons 8-10
pH
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pH is a scale used by scientists to
measure the acidity or basicity of
a substance
pH 7 is neutral
pH 1 up to pH 7 is acidic
pH greater than 7 up to pH 14 is
basic
pH
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pH is a chemical property
pH is used to predict chemical
reactions or to select compounds
for specific chemical reactions
Acids and bases are reactive
compounds
Physical and Chemical
Changes
Physical Changes
Any change in size, shape,
form, or state of matter
 The makeup of the matter stays
the same, only the physical
properties change
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Examples of Physical Changes
Physical weathering
 Cutting or breaking
something
 Change in state
of matter
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Changes in State of Matter
Solid to liquid – melting
 Liquid to gas – evaporating or
boiling
 Gas to liquid – condensation
 Liquid to solid – freezing or
solidifying
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Chemical Changes
Any change where one or more
of the original materials
changes into a new material
 They can take place quickly or
slowly (rusting)
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Signs of chemical changes
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Heat or light can be released
Signs of chemical changes
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A new substance can be formed – a gas
is released, a solid or liquid forms
More signs of chemical
changes
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Sometimes heat (energy) is absorbed
Sometimes a color change happens
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Link to a site with short lessons about
chemical reactions
http://www.middleschoolchemistry.com
/multimedia/chapter6/lesson1
Lessons 1-7